Field of the Invention
The present invention generally relates to respiratory devices. More particularly, the present invention relates to respiratory devices in which respiratory gases are supplied at a positive pressure after passing over a surface of liquid in a reservoir.
Description of the Related Art
CPAP treatment of obstructive sleep apnea involves the delivery of pressurized, breathable gas, usually air, to a user's airways using a conduit and a user interface, such as a mask. The gas pressures employed for CPAP typically range from about 4 cm H2O to about 28 cm H2O at flow rates of up to about 180 L/min (measured at the user interface), depend upon the requirements of the user. The pressurized gas acts as a pneumatic splint for the airway of the user. As such, the pressurized gas reduces the likelihood of collapsing of the airway.